Switch bindings implementation to nanobind (google#1526)

* End support for Python 3.7, update cibuildwheel and publish actions

Removes Python 3.7 from the support matrix, since it does not support
PEP590 vectorcalls.

Bumps the `cibuildwheel` and `pypa-publish` actions to their latest
available versions respectively.

* Add nanobind to the Bazel dependencies, add a BUILD file

The build file builds nanobind as a static `cc_library`. Currently,
the git SHA points to HEAD, since some necessary features have not
been included in a release yet.

* Delete pybind11 BUILD file

* Switch bindings implementation to nanobind

Switches over the binding tool to `nanobind` from `pybind11`. Most
changes in the build setup itself were drop-in replacements of existing
code changed to nanobind names, no new concepts needed to be
implemented.

Sets the minimum required macOS to 10.14 for full C++17 support. Also,
to avoid ambiguities in Bazel, build for macOS 11 on Mac ARM64.

* Use Bazel select for linker options

Guards against unknown linker option errors by selecting required
linker options for nanobind only on macOS, where they are relevant.

Other changes:
* Bump cibuildwheel action to v2.12.0
* Bump Bazel for aarch64 linux wheels to 6.0.0
* Remove C++17 flag from build files since it is present in setup.py `bazel build` command
* Bump nanobind commit to current HEAD (TBD: Bump to next stable release)

* Unbreak Windows builds of nanobind-based bindings

Guards compiler options behind a new `select` macro choosing between
MSVC and not MSVC.

Other changes:
* Inject the proper C++17 standard cxxopt in the `setup.py` build
command.
* Bump nanobind to current HEAD.
* Make `macos` a benchmark-wide condition, with public visibility to
allow its use in the nanobind BUILD file.

* Fall back to `nb::implicitly_convertible` for Counter construction

Since `benchmark::Counter` only has a constructor for `double`,
the nanobind `nb::init_implicit` template cannot be used. Therefore,
to support implicit construction from ints, we fall back to the
`nb::implicitly_convertible` template instead.

.github/install_bazel.sh

@@ -5,7 +5,7 @@ if ! bazel version; then
   fi
   echo "Installing wget and downloading $arch Bazel binary from GitHub releases."
   yum install -y wget
-  wget "https://github.com/bazelbuild/bazel/releases/download/5.2.0/bazel-5.2.0-linux-$arch" -O /usr/local/bin/bazel
+  wget "https://github.com/bazelbuild/bazel/releases/download/6.0.0/bazel-6.0.0-linux-$arch" -O /usr/local/bin/bazel
   chmod +x /usr/local/bin/bazel
 else
   # bazel is installed for the correct architecture

.github/workflows/test_bindings.yml

@@ -11,6 +11,7 @@ jobs:
     name: Test GBM Python bindings on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
 

.github/workflows/wheels.yml

@@ -14,10 +14,10 @@ jobs:
       - name: Check out repo
         uses: actions/checkout@v3
 
-      - name: Install Python 3.9
-        uses: actions/setup-python@v3
+      - name: Install Python 3.11
+        uses: actions/setup-python@v4
         with:
-          python-version: 3.9
+          python-version: 3.11
 
       - name: Build and check sdist
         run: |
@@ -46,11 +46,11 @@ jobs:
           platforms: all
 
       - name: Build wheels on ${{ matrix.os }} using cibuildwheel
-        uses: pypa/cibuildwheel@v2.9.0
+        uses: pypa/cibuildwheel@v2.12.0
         env:
-          CIBW_BUILD: 'cp37-* cp38-* cp39-* cp310-* cp311-*'
-          CIBW_SKIP: "cp37-*-arm64 *-musllinux_*"
-          # TODO: Build ppc64le using some other trick
+          CIBW_BUILD: 'cp38-* cp39-* cp310-* cp311-*'
+          CIBW_SKIP: "*-musllinux_*"
+          CIBW_TEST_SKIP: "*-macosx_arm64"
           CIBW_ARCHS_LINUX: x86_64 aarch64
           CIBW_ARCHS_MACOS: x86_64 arm64
           CIBW_ARCHS_WINDOWS: AMD64
@@ -73,7 +73,7 @@ jobs:
         name: dist
         path: dist
 
-    - uses: pypa/gh-action-pypi-publish@v1.5.0
+    - uses: pypa/gh-action-pypi-publish@v1.6.4
       with:
         user: __token__
         password: ${{ secrets.PYPI_PASSWORD }}

BUILD.bazel

@@ -18,6 +18,12 @@ config_setting(
     visibility = [":__subpackages__"],
 )
 
+config_setting(
+    name = "macos",
+    constraint_values = ["@platforms//os:macos"],
+    visibility = ["//visibility:public"],
+)
+
 config_setting(
     name = "perfcounters",
     define_values = {

bazel/benchmark_deps.bzl

@@ -44,13 +44,13 @@ def benchmark_deps():
             tag = "release-1.11.0",
         )
 
-    if "pybind11" not in native.existing_rules():
-        http_archive(
-            name = "pybind11",
-            build_file = "@//bindings/python:pybind11.BUILD",
-            sha256 = "eacf582fa8f696227988d08cfc46121770823839fe9e301a20fbce67e7cd70ec",
-            strip_prefix = "pybind11-2.10.0",
-            urls = ["https://github.com/pybind/pybind11/archive/v2.10.0.tar.gz"],
+    if "nanobind" not in native.existing_rules():
+        git_repository(
+            name = "nanobind",
+            remote = "https://github.com/wjakob/nanobind.git",
+            commit = "fe3ecb800a7a3e8023e8ee77167a6241591e0b8b",
+            build_file = "@//bindings/python:nanobind.BUILD",
+            recursive_init_submodules = True,
         )
 
     if "libpfm" not in native.existing_rules():

bindings/python/google_benchmark/BUILD

@@ -6,7 +6,6 @@ py_library(
     visibility = ["//visibility:public"],
     deps = [
         ":_benchmark",
-        # pip; absl:app
     ],
 )
 
@@ -17,10 +16,13 @@ py_extension(
         "-fexceptions",
         "-fno-strict-aliasing",
     ],
-    features = ["-use_header_modules"],
+    features = [
+        "-use_header_modules",
+        "-parse_headers",
+    ],
     deps = [
         "//:benchmark",
-        "@pybind11",
+        "@nanobind",
         "@python_headers",
     ],
 )

bindings/python/google_benchmark/benchmark.cc

@@ -2,19 +2,16 @@
 
 #include "benchmark/benchmark.h"
 
-#include <map>
-#include <string>
-#include <vector>
+#include "nanobind/nanobind.h"
+#include "nanobind/operators.h"
+#include "nanobind/stl/bind_map.h"
+#include "nanobind/stl/string.h"
+#include "nanobind/stl/vector.h"
 
-#include "pybind11/operators.h"
-#include "pybind11/pybind11.h"
-#include "pybind11/stl.h"
-#include "pybind11/stl_bind.h"
-
-PYBIND11_MAKE_OPAQUE(benchmark::UserCounters);
+NB_MAKE_OPAQUE(benchmark::UserCounters);
 
 namespace {
-namespace py = ::pybind11;
+namespace nb = nanobind;
 
 std::vector<std::string> Initialize(const std::vector<std::string>& argv) {
   // The `argv` pointers here become invalid when this function returns, but
@@ -38,89 +35,90 @@ std::vector<std::string> Initialize(const std::vector<std::string>& argv) {
 }
 
 benchmark::internal::Benchmark* RegisterBenchmark(const char* name,
-                                                  py::function f) {
+                                                  nb::callable f) {
   return benchmark::RegisterBenchmark(
       name, [f](benchmark::State& state) { f(&state); });
 }
 
-PYBIND11_MODULE(_benchmark, m) {
+NB_MODULE(_benchmark, m) {
+
   using benchmark::TimeUnit;
-  py::enum_<TimeUnit>(m, "TimeUnit")
+  nb::enum_<TimeUnit>(m, "TimeUnit")
       .value("kNanosecond", TimeUnit::kNanosecond)
       .value("kMicrosecond", TimeUnit::kMicrosecond)
       .value("kMillisecond", TimeUnit::kMillisecond)
       .value("kSecond", TimeUnit::kSecond)
       .export_values();
 
   using benchmark::BigO;
-  py::enum_<BigO>(m, "BigO")
+  nb::enum_<BigO>(m, "BigO")
       .value("oNone", BigO::oNone)
       .value("o1", BigO::o1)
       .value("oN", BigO::oN)
       .value("oNSquared", BigO::oNSquared)
       .value("oNCubed", BigO::oNCubed)
       .value("oLogN", BigO::oLogN)
-      .value("oNLogN", BigO::oLogN)
+      .value("oNLogN", BigO::oNLogN)
       .value("oAuto", BigO::oAuto)
       .value("oLambda", BigO::oLambda)
       .export_values();
 
   using benchmark::internal::Benchmark;
-  py::class_<Benchmark>(m, "Benchmark")
-      // For methods returning a pointer tor the current object, reference
-      // return policy is used to ask pybind not to take ownership oof the
+  nb::class_<Benchmark>(m, "Benchmark")
+      // For methods returning a pointer to the current object, reference
+      // return policy is used to ask nanobind not to take ownership of the
       // returned object and avoid calling delete on it.
       // https://pybind11.readthedocs.io/en/stable/advanced/functions.html#return-value-policies
       //
       // For methods taking a const std::vector<...>&, a copy is created
       // because a it is bound to a Python list.
       // https://pybind11.readthedocs.io/en/stable/advanced/cast/stl.html
-      .def("unit", &Benchmark::Unit, py::return_value_policy::reference)
-      .def("arg", &Benchmark::Arg, py::return_value_policy::reference)
-      .def("args", &Benchmark::Args, py::return_value_policy::reference)
-      .def("range", &Benchmark::Range, py::return_value_policy::reference,
-           py::arg("start"), py::arg("limit"))
+      .def("unit", &Benchmark::Unit, nb::rv_policy::reference)
+      .def("arg", &Benchmark::Arg, nb::rv_policy::reference)
+      .def("args", &Benchmark::Args, nb::rv_policy::reference)
+      .def("range", &Benchmark::Range, nb::rv_policy::reference,
+           nb::arg("start"), nb::arg("limit"))
       .def("dense_range", &Benchmark::DenseRange,
-           py::return_value_policy::reference, py::arg("start"),
-           py::arg("limit"), py::arg("step") = 1)
-      .def("ranges", &Benchmark::Ranges, py::return_value_policy::reference)
+           nb::rv_policy::reference, nb::arg("start"),
+           nb::arg("limit"), nb::arg("step") = 1)
+      .def("ranges", &Benchmark::Ranges, nb::rv_policy::reference)
       .def("args_product", &Benchmark::ArgsProduct,
-           py::return_value_policy::reference)
-      .def("arg_name", &Benchmark::ArgName, py::return_value_policy::reference)
+           nb::rv_policy::reference)
+      .def("arg_name", &Benchmark::ArgName, nb::rv_policy::reference)
       .def("arg_names", &Benchmark::ArgNames,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("range_pair", &Benchmark::RangePair,
-           py::return_value_policy::reference, py::arg("lo1"), py::arg("hi1"),
-           py::arg("lo2"), py::arg("hi2"))
+           nb::rv_policy::reference, nb::arg("lo1"), nb::arg("hi1"),
+           nb::arg("lo2"), nb::arg("hi2"))
       .def("range_multiplier", &Benchmark::RangeMultiplier,
-           py::return_value_policy::reference)
-      .def("min_time", &Benchmark::MinTime, py::return_value_policy::reference)
+           nb::rv_policy::reference)
+      .def("min_time", &Benchmark::MinTime, nb::rv_policy::reference)
       .def("min_warmup_time", &Benchmark::MinWarmUpTime,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("iterations", &Benchmark::Iterations,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("repetitions", &Benchmark::Repetitions,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("report_aggregates_only", &Benchmark::ReportAggregatesOnly,
-           py::return_value_policy::reference, py::arg("value") = true)
+           nb::rv_policy::reference, nb::arg("value") = true)
       .def("display_aggregates_only", &Benchmark::DisplayAggregatesOnly,
-           py::return_value_policy::reference, py::arg("value") = true)
+           nb::rv_policy::reference, nb::arg("value") = true)
       .def("measure_process_cpu_time", &Benchmark::MeasureProcessCPUTime,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("use_real_time", &Benchmark::UseRealTime,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def("use_manual_time", &Benchmark::UseManualTime,
-           py::return_value_policy::reference)
+           nb::rv_policy::reference)
       .def(
           "complexity",
           (Benchmark * (Benchmark::*)(benchmark::BigO)) & Benchmark::Complexity,
-          py::return_value_policy::reference,
-          py::arg("complexity") = benchmark::oAuto);
+          nb::rv_policy::reference,
+          nb::arg("complexity") = benchmark::oAuto);
 
   using benchmark::Counter;
-  py::class_<Counter> py_counter(m, "Counter");
+  nb::class_<Counter> py_counter(m, "Counter");
 
-  py::enum_<Counter::Flags>(py_counter, "Flags")
+  nb::enum_<Counter::Flags>(py_counter, "Flags")
       .value("kDefaults", Counter::Flags::kDefaults)
       .value("kIsRate", Counter::Flags::kIsRate)
       .value("kAvgThreads", Counter::Flags::kAvgThreads)
@@ -132,28 +130,29 @@ PYBIND11_MODULE(_benchmark, m) {
       .value("kAvgIterationsRate", Counter::Flags::kAvgIterationsRate)
       .value("kInvert", Counter::Flags::kInvert)
       .export_values()
-      .def(py::self | py::self);
+      .def(nb::self | nb::self);
 
-  py::enum_<Counter::OneK>(py_counter, "OneK")
+  nb::enum_<Counter::OneK>(py_counter, "OneK")
       .value("kIs1000", Counter::OneK::kIs1000)
       .value("kIs1024", Counter::OneK::kIs1024)
       .export_values();
 
   py_counter
-      .def(py::init<double, Counter::Flags, Counter::OneK>(),
-           py::arg("value") = 0., py::arg("flags") = Counter::kDefaults,
-           py::arg("k") = Counter::kIs1000)
-      .def(py::init([](double value) { return Counter(value); }))
+      .def(nb::init<double, Counter::Flags, Counter::OneK>(),
+           nb::arg("value") = 0., nb::arg("flags") = Counter::kDefaults,
+           nb::arg("k") = Counter::kIs1000)
+      .def("__init__", ([](Counter *c, double value) { new (c) Counter(value); }))
       .def_readwrite("value", &Counter::value)
       .def_readwrite("flags", &Counter::flags)
-      .def_readwrite("oneK", &Counter::oneK);
-  py::implicitly_convertible<py::float_, Counter>();
-  py::implicitly_convertible<py::int_, Counter>();
+      .def_readwrite("oneK", &Counter::oneK)
+      .def(nb::init_implicit<double>());
+
+  nb::implicitly_convertible<nb::int_, Counter>();
 
-  py::bind_map<benchmark::UserCounters>(m, "UserCounters");
+  nb::bind_map<benchmark::UserCounters>(m, "UserCounters");
 
   using benchmark::State;
-  py::class_<State>(m, "State")
+  nb::class_<State>(m, "State")
       .def("__bool__", &State::KeepRunning)
       .def_property_readonly("keep_running", &State::KeepRunning)
       .def("pause_timing", &State::PauseTiming)
@@ -168,15 +167,16 @@ PYBIND11_MODULE(_benchmark, m) {
       .def_property("items_processed", &State::items_processed,
                     &State::SetItemsProcessed)
       .def("set_label", (void (State::*)(const char*)) & State::SetLabel)
-      .def("range", &State::range, py::arg("pos") = 0)
+      .def("range", &State::range, nb::arg("pos") = 0)
       .def_property_readonly("iterations", &State::iterations)
+      .def_property_readonly("name", &State::name)
       .def_readwrite("counters", &State::counters)
       .def_property_readonly("thread_index", &State::thread_index)
       .def_property_readonly("threads", &State::threads);
 
   m.def("Initialize", Initialize);
   m.def("RegisterBenchmark", RegisterBenchmark,
-        py::return_value_policy::reference);
+        nb::rv_policy::reference);
   m.def("RunSpecifiedBenchmarks",
         []() { benchmark::RunSpecifiedBenchmarks(); });
   m.def("ClearRegisteredBenchmarks", benchmark::ClearRegisteredBenchmarks);

bindings/python/nanobind.BUILD

@@ -0,0 +1,52 @@
+
+config_setting(
+    name = "msvc_compiler",
+    flag_values = {"@bazel_tools//tools/cpp:compiler": "msvc-cl"},
+)
+
+cc_library(
+    name = "nanobind",
+    hdrs = glob(
+        include = [
+            "include/nanobind/*.h",
+            "include/nanobind/stl/*.h",
+            "include/nanobind/detail/*.h",
+        ],
+        exclude = [],
+    ),
+    srcs = [
+        "include/nanobind/stl/detail/nb_dict.h",
+        "include/nanobind/stl/detail/nb_list.h",
+        "include/nanobind/stl/detail/traits.h",
+        "ext/robin_map/include/tsl/robin_map.h",
+        "ext/robin_map/include/tsl/robin_hash.h",
+        "ext/robin_map/include/tsl/robin_growth_policy.h",
+        "ext/robin_map/include/tsl/robin_set.h",
+        "src/buffer.h",
+        "src/common.cpp",
+        "src/error.cpp",
+        "src/implicit.cpp",
+        "src/nb_enum.cpp",
+        "src/nb_func.cpp",
+        "src/nb_internals.cpp",
+        "src/nb_internals.h",
+        "src/nb_type.cpp",
+        "src/tensor.cpp",
+        "src/trampoline.cpp",
+    ],
+    copts = select({
+        ":msvc_compiler": [],
+        "//conditions:default": [
+        "-fexceptions",
+        "-Os",  # size optimization
+        "-flto", # enable LTO
+        ],
+    }),
+    linkopts = select({
+        "@com_github_google_benchmark//:macos": ["-undefined suppress", "-flat_namespace"],
+        "//conditions:default": [],
+    }),
+    includes = ["include", "ext/robin_map/include"],
+    deps = ["@python_headers"],
+    visibility = ["//visibility:public"],
+)